Esophageal balloon catheter device

ABSTRACT

An esophageal catheter device including a catheter with a balloon pressure sensor affixed to an exterior surface of the catheter, and a stylet assembly including a stylet for providing appropriate rigidity to the catheter to aid insertion in the esophagus and a port for removably mounting a pressure transducer.

FIELD OF THE INVENTION

[0001] The present invention relates to a device that provides a conduitthrough which intra-thoracic pressures can be monitored and measured.More particularly, the present invention relates to an improvedesophageal balloon catheter device that is used to obtain esophagealpressure data for evaluating, treating and diagnosing patients withvarious respiratory conditions and diseases.

BACKGROUND OF THE INVENTION

[0002] Esophageal balloon catheter devices are commonly used as aresearch or clinical tool in the study of lung mechanics. Specifically,many investigators have utilized esophageal balloons to characterize themechanical properties of the lung in both health and in disease as wellas in determining the work or effort of breathing.

[0003] More recently, esophageal balloon catheter devices have been usedas part of monitoring systems for diagnosing sleep disorders, theclinical management of ventilator patients, as well as a part ofpulmonary function systems in the measurement of lung mechanics.

[0004] Typical esophageal balloon catheter devices employ anair-containing balloon sealed over the distal or near distal end of acatheter that transmits balloon pressure to a pressure transducerattached to the proximal end of the catheter. A pressure transducer inthis context converts mechanical energy (balloon pressure) intoelectrical signals and units of measurement. The balloon of the catheteris usually positioned in the lower or middle third of the esophagus tomonitor esophageal pressure to determine lung compliance and respiratoryeffort. As is known; during inhalation the pressure in the esophagus andthorax decreases, while it increases in the viscera below the diaphragmand during exhalation the pressure in the esophagus and thorax increaseswhile it decreases in the viscera below the diaphragm

[0005] The catheter used in these devices is sometimes constructed to bestiff and rigid enough to allow insertion through the nasal passage anddown into the esophagus. A serious disadvantage of these devices is thatthey are uncomfortable to patients being monitored to an extent that thepressure data may be affected as well as the patient's ability to sleep.The catheter used in these devices may also be constructed to be limpand flaccid to provide comfort during overnight esophageal pressuretesting. However, the limp and flaccid nature of the catheter makes itvirtually impossible to insert it into the esophagus. Accordingly, sucha catheter device includes a removable stylet assembly, which consistsof a wire that is inserted into the lumen of the catheter at theproximal end thereof to stiffen the catheter so that it can be insertedinto the esophagus and the balloon properly positioned therein. Once theballoon of the catheter device is positioned in the esophagus, thestylet assembly needs to be removed so the pressure transducer can beattached to the proximal end of the catheter.

[0006] A major disadvantage of these devices is that it is verydifficult to position the balloon correctly in the esophagus. There isan advantage in being able to monitor esophageal pressure oscillationwhile positioning the balloon in the esophagus. This is possible withthe stiffer more rigid catheters but not with the more comfortable softand flaccid catheters. Once the stylet is removed and the pressuretransducer attached, it is often discovered that the balloon is notproperly positioned in the esophagus. Because the catheter is so softand flaccid this necessitates removing the pressure transducer andreinserting the stylet into the catheter to stiffen it so that theposition of the balloon can be corrected. Unfortunately, reinserting thestylet assembly into the catheter is extremely dangerous as it canpuncture the catheter and the esophagus.

[0007] Accordingly, there is a need for an improved esophageal ballooncatheter device, which is soft and flaccid for comfort and yet allowsfor monitoring esophageal pressure oscillation to aid proper positioningof the balloon. Such a device would avoid the need for removal of thestylet to attach the pressure transducer and the subsequent risk ofreinserting the stylet assembly for balloon repositioning.

SUMMARY OF THE INVENTION

[0008] An esophageal catheter device comprises a catheter with a balloonas pressure sensor affixed to an exterior surface of the catheter, and astylet assembly including a stylet for preventing bending and flexing ofthe catheter during insertion in the esophagus and a port for removablyattaching a pressure transducer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The advantages, nature, and various additional features of theinvention will appear more fully upon consideration of the illustrativeembodiments now to be described in detail in connection withaccompanying drawings wherein:

[0010]FIG. 1 is an elevational view of an esophageal balloon catheterdevice according to an exemplary embodiment of the present invention;

[0011]FIG. 2 is a sectional view of a balloon air pressure sensoraccording to an exemplary embodiment of the catheter device of thepresent invention;

[0012]FIG. 3 is a side elevational view of an exemplary stylettransducer coupler assembly according to an exemplary embodiment of thecatheter device of the present invention;

[0013]FIG. 4 is a side elevational view showing a pressure transducermounted to the transducer port of the coupler assembly; and

[0014]FIG. 5 is a side elevational view showing a pressure transducermounted to a hub connector of the catheter device.

DETAILED DESCRIPTION OF THE INVENTION

[0015] Referring to the drawings wherein like reference numeralsidentify similar or like elements throughout the several views andinitially to FIG. 1, there is shown an esophageal balloon catheterdevice 10 according to an exemplary embodiment of the invention. Thecatheter device 10 generally comprises a catheter 12, a pressure sensor14 sealingly affixed to the exterior surface of the catheter 12 in aconventional manner, and a stylet transducer coupler assembly 16 havinga transducer port 18 for mounting a pressure transducer which may beused for correctly positioning the pressure sensor 14 of the device inthe esophagus. The ability to attach a pressure transducer to thecoupler assembly 16 substantially eliminates the need for guess workwhen placing the pressure sensor 14 in the esophagus.

[0016] The catheter 12 typically comprises a 5 french, pliable and softtubular body 20 which maximizes patient comfort and minimizes effects onnormal breathing. The catheter 12 has a length which, in one exemplaryembodiment, may be about 87 cm when sized for an adult. A conventionalfemale Luer hub connector 22 or other suitable connector may be providedat a proximal end 24 of the catheter 12 for permitting a pressuretransducer to be easily connected to the catheter 12 as explainedfurther on. As shown in FIG. 2, the catheter 12 defines an inflationlumen 26 that typically extends within the catheter 12 such that itcommunicates with the interior of the pressure sensor 14 via one or moreopenings 28 located in a wall portion of the catheter 12 enclosed by thepressure sensor 14.

[0017] The catheter 12 is preferably made from a radio-opaque materialsuch as poly(vinyl chloride) or polyurethane. The catheter 12 may beprovided with a plurality of depth markings 30, typically in the form ofcircumferential gradations. The markings 30 are preferably of a typethat can be easily seen, therefore, further aiding the user of thecatheter device 10 to appropriately position the pressure sensor 14within the esophagus or other part of the body of the patient.

[0018] The pressure sensor 14 preferably comprises an elongated balloon15 element having a length which is typically about 10 cm and about 3-4cc in air capacity, although the exact size of the balloon 14 may beselected so that when positioned within the esophagus, it occupies thelower third of the thorax to properly represent intra-thoracic pressureoscillation independent of cardiac oscillation. The balloon 15 may bemade from a soft, preferably latex free material such as poly(vinylchloride) or polyurethane. The distal-most end 32 of the pressure sensor14 is located about 5 cm from the distal end of the catheter 12 offeringa thin lead ahead of the balloon to ease passage through the nasalpassages, oral pharynx and esophagus.

[0019] In operation, the pressure sensor 14 of the catheter device 10monitors esophageal pressure in the following manner. The balloon 15 isonly partially filled with air (about 1 cc) as it rests inside theesophagus. During inhalation intra-thoracic pressure becomessub-atmospheric (negative). The sub-atmospheric pressure is applied tothe walls of the pressure sensor balloon attempting to more fully expandor fill the balloon. During exhalation intra-thoracic pressure becomespositive. The positive pressure is applied to the walls of the pressuresensor balloon attempting to collapse or empty the balloon. The conduitdefined by the inflation lumen 26 of the catheter 12 connects thepressure sensor balloon 14 to a transducer attached to the port 18. Itis important that the pressure sensor balloon has the correct amount ofresidual air so slight changes in intra-thoracic pressures aretransmitted to the transducer without the distortion of any elasticproperties from the balloon wall stretching. The lumen 26 channels airand pressure into the balloon 15 through the one or more openings 28 inthe catheter wall that pass directly to the inside of the balloon 15.The pressure in the balloon 15 is transmitted to the proximal end of thelumen 26 which communicates with a pressure transducer 50 via the stylettransducer coupler assembly 16 as shown in FIG. 4 or via the hubconnector 22 as shown in FIG. 5. The pressure transducer converts thepositive and negative esophageal pressure oscillations (mechanicalenergy) to electronic signals and units of pressure. The esophagealpressures of the person receiving the catheter device 10 will bereflected by air pressure changes within the balloon 15.

[0020] As shown in FIG. 3, the stylet transducer coupler assembly 16 ofthe catheter device 10 comprises a coupler 34 and a stylet 36. Thecoupler 34 includes a substantially straight main tube section 38 havingdistal 40 and proximal ends 42, and the earlier mentioned transducerport tube 18. The distal end 40 of the main tube section 38 is taperedto permit the coupler 34 to be received within the hub connector 22 ofthe catheter 12 in a friction fit manner. The proximal end 42 of themain tube section 38 is sealed by a cap-like closure 44. The stylet 36is a wire-like member, the proximal end of which may be permanentlyaffixed to a cylindrical portion 46 of the closure 44 extending into themain tube section 38.

[0021] The stylet 36 of the transducer coupler assembly 16 is threadedthrough the inflation lumen 26 of the catheter 12 (FIG. 2) addingrigidity to the catheter 12, hence aiding the insertion thereof into theesophagus and the positioning of the pressure sensor 14 therein. It ispreferred that the distal end 48 of the stylet 36 be blunt (FIG. 2),with a rounded tip, and that the entire stylet be coated with PTFE toaid in removing it from the inflation lumen 26 after the balloon isproperly placed.

[0022] The transducer port 18 of the stylet coupler assembly 16 isadapted to accept a standard pressure transducer 50 to the couplerassembly 16 so that the transducer 50, in conjunction with the pressuresensor 14, may be used in concert for correctly positioning the pressuresensor in the esophagus. Once the pressure sensor is correctlypositioned in the esophagus, the pressure transducer 50 is then removedfrom the port 18 of the coupler assembly 16. The stylet transducercoupler assembly 16 is withdrawn from the catheter 12. The pressuretransducer 50 may then be attached to the connector 22 of the catheter12 and operated in conjunction with the pressure sensor 14 to monitoresophageal pressure.

[0023] While the foregoing invention has been described with referenceto the above embodiments, various modifications and changes can be madewithout departing from the spirit of the invention. Accordingly, allsuch modifications and changes are considered to be within the scope ofthe appended claims.

What is claimed is:
 1. An esophageal catheter device comprising: acatheter including an open end and a closed end, the closed end forremovably mounting one of a pressure transducer and removably receivinga stylet; a balloon affixed to an exterior surface of the catheter, theballoon useable as a pressure sensor; a balloon inflation lumenextending through the catheter in communication with the interior of theballoon through at least one aperture extending through the catheter;and a stylet assembly including a stylet for providing appropriaterigidity to the catheter to aid insertion into the esophagus and a portfor removably mounting a pressure transducer.
 2. The esophageal catheterdevice according to claim 1, wherein the stylet assembly furtherincludes a coupler.
 3. The esophageal catheter device according to claim2, wherein the coupler includes the port for mounting the pressuretransducer.
 4. The esophageal catheter device according to claim 2,wherein the coupler includes a main tube section, the port for mountingthe pressure transducer extending from the main tube section.
 5. Theesophageal catheter device according to claim 1, wherein the catheterincludes a plurality of depth markings.
 6. The esophageal catheterdevice according to claim 1, wherein the stylet assembly furtherincludes a coupler and a closure sealing an end of the coupler, thestylet having an end affixed to a portion of the closure.
 7. Theesophageal catheter device according to claim 6, wherein the couplerincludes the port for mounting the pressure transducer.
 8. Theesophageal catheter device according to claim 1, further comprising ahub connector disposed at the open end of the catheter.
 9. Theesophageal catheter device according to claim 1, wherein the catheter ismade from a radio-opaque material.
 10. The esophageal catheter deviceaccording to claim 1, wherein the balloon is made from a latex-freematerial.
 11. A stylet assembly for an esophageal catheter device havinga balloon affixed to an exterior surface of the catheter, the balloonuseable as a pressure sensor; the stylet assembly comprising: a coupler;a stylet having an end affixed to the coupler; and a port extending fromthe coupler for removably mounting a pressure transducer.
 12. The styletassembly according to claim 11, wherein the coupler includes a main tubesection, the port for mounting the pressure transducer extending fromthe main tube section.
 13. The stylet assembly according to claim 11,wherein the stylet assembly further includes a closure sealing an end ofthe coupler, the stylet having an end affixed to a portion of theclosure.
 14. A method for intra-thoracic pressure monitoring, the methodcomprising the steps of: providing an esophageal catheter deviceincluding a catheter, a balloon affixed to an exterior surface of thecatheter, the balloon useable as a pressure sensor, a balloon inflationlumen extending through the catheter in communication with the interiorof the balloon through at least one aperture extending through thecatheter, and a stylet assembly including a stylet for providingappropriate rigidity to the catheter to aid insertion in the esophagusand a port for removably mounting a pressure transducer; mounting apressure transducer to the port of the stylet assembly; inserting thecatheter device into an esophagus; adding the correct amount of air tothe sensor balloon; positioning the sensor balloon of the catheterdevice in a desired location in the esophagus using pressure informationobtained through the sensor balloon, the stylet assembly and pressuretransducer working in concert.
 15. The method according to claim 14,further comprising the steps of: removing the pressure transducer fromthe port; removing the stylet assembly from the open end of thecatheter; mounting the pressure transducer to the open end of thecatheter; and monitoring esophageal pressure using pressure informationobtained through the sensor balloon and the pressure transducer workingin concert.
 16. The method according to claim 14, wherein the styletassembly further includes a coupler.
 17. The method according to claim16, wherein the coupler includes the port for mounting the pressuretransducer.
 18. The method according to claim 16, wherein the couplerincludes a main tube section, the port for mounting the pressuretransducer extending from the main tube section.
 19. The methodaccording to claim 14, wherein the catheter is made from a radio-opaquematerial.
 20. The method according to claim 14, wherein the balloon ismade from a latex-free material.